#1 22-250 Rate of twist question??????

[BearStopper]

What is the rate of twist on my mid 70's #1B 22-250 and what is the general consensus on the heaviest bullet it will stabilize for long range varminting?

 

[four70nitro]

I believe they are 1 in 14, but they may be 1 in 12.....I am fairly certain that my .220 Swift has a 14 inch twist. I know I've shot 55's and 60's in the Swift with good results. I don't know what the heaviest bullet that will stabilize in a 14 inch twist is.....